Jing, F. E. N. G., & Tim, L. I. (2016). INITIATION MECHANISMS FOR A SUCCESSIVE MJO EVENT AND A PRIMARY MJO EVENT DURING BOREAL WINTER OF 2000-2001. Journal of Tropical Meteorology, 22(4).
INITIATION MECHANISMS FOR A SUCCESSIVE MJO EVENT AND A PRIMARY MJO EVENT DURING BOREAL WINTER OF 2000-2001
FENG Jing (冯 婧)1, 3, Tim LI (李天明)1, 2
(1. Key Laboratory of Meteorological Disaster, Ministry of Education / Joint International Research
Laboratory of Climate and Environmental Change/ Collaborative Innovation Center on Forecast and
Evaluation of Meteorological Disasters, Nanjing University of Information Science and Technology,
Nanjing 210044 China; 2. International Pacific ResearchCenter and Department of Atmospheric Sciences, University of Hawaii at Manoa, Honolulu, Hawaii; 3.Beijing Meteorological Information Center, Beijing Meteorological Information Network Center, Beijing 100089 China)
Abstract: Observed outgoing longwave radiation (OLR) and ERA-Interim reanalysis data were analyzed to reveal the initiation processes associated with a successive and a primary MJO event during 2000-2001. It was found that the initiation of the successive event was caused by anomalous ascending motion induced by low-level horizontal temperature advection. The anomalous ascending motion, together with horizontal moisture advection, moistened lower troposphere and led to an unstable stratification and triggered convection. The initiation of the primary MJO event, on the other hand, was caused by the accumulation of anomalous moisture associated with three low-frequency modes, a convectively coupled Kelvin wave (CCKW), an westward-propagating equatorial Rossby wave (ER) and a weak planetary-scale MJO mode. It is the merging of the low-level specific humidity anomalies of the three modes that led to the rapid setup of large-scale convectively unstable stratification and favored the development of the eastward-propagating planetary-scale MJO mode.
Key words: convection initiation; successive MJO; primary MJO